making an umbrella in blender
If the Sheen effect is not enough maybe you should plug an Input > Layer Weight > Fresnel in the factor of a Mix between a Glossy and a Diffuse (or a Principled BSDF). To give transparency mix with a Translucent node before the end, the fabric will only seem transparent if you face the light source. Also maybe you should use a Wave node to create a discrete polyester fabric texture (just some parallel stripes).